This invention relates to a reed relay where adjacent pairs of reed switches are utilized, as for low level voltage measurement and data scanning applications wherein two low-level signal lines are involved. Such reed switches generally are comprised of two flexible metal reeds hermetically sealed and supported in a glass enclosure so that the reeds are mechanically held apart except in the presence of a magnetic field in turn generally provided by a drive coil positioned about the enclosure or bobbin in which such reed switches are commonly housed. Such reeds generally consist of an iron-nickel alloy, i.e., "Niron". Extensions of the reeds are brought out through the glass enclosure at opposite ends thereof and form the ends of the reed switch. Thermal electrically-active junctions are formed when lead wires from an external circuit usually formed of copper or the like are connected to the iron-nickel ends of the reeds. When a temperature differential is created across these junctions such as may be created from heat dissipated in the drive coil, conductive air currents, and other such causes of ambient temperature gradients, a thermal EMF is generated which in many cases may be sufficiently large in proportion to the signal being measured or otherwise utilized so as to adversely affect operation of the relay. Accordingly it is highly desirable to eliminate or at least minimize to usable levels such thermal EMF effect.
It is known, for example, as disclosed in U.S. Pat. No. 3,456,216, to interconnect in series a pair of reed switches in such a fashion that the thermal junctions are made at the same end of the reed enclosure body and in this fashion temperature differentials and accordingly the thermal EMFs would be substantially reduced. It is also known in the art, as disclosed in U.S. Pat. No. 3,701,960, assigned to the assignee of the present application, to thermally interconnect the opposed outwardly extending leads of such a reed switch to substantially balance the temperatures of such leads and accordingly satisfactorily eliminate or cancel out the thermal EMFs in such environments. However, such above indicated disclosures do not directly pertain to a commonly utilized parallel type circuit wherein a pair of such reed switches may be placed in parallel connection with the lead wires of an external circuit for direct measurement of low level voltages or for data scanning applications.